Light signal



April 24, 1928. 1,667,469

P. E. CARTER LIGHT SIGNAL Original Filed Nov. 9, 1921 2 Sheets-Sheet 1 m... u 2 a FIG.2.

14 25" a1 26 27 2a 25 2s E7 2511 of 28 a as 30.

$5 A'TTORNEY.

April 24, 1928. r 1,667,469

P. E. CARTER LIGHT SIGNAL Original Filed Nov. 9, 1921 2 Sheets-Sheet 2 A TTORNE Y.

Patented Apr.24,1928. s a 7 1,667,469 I UNITED STATES ATENT OFFICIEQ f PAUL n. CARTER, on nrionxvrnnn; NEW YonK, assmnonmoiennnnnn RAILW Y" srenan COMPANY; or GATES, New YORK, A conronaron ornnwyonx,

LIGHT SIGNAL. Application. filed Noveniber 9, 1921; Serial No. 514,053. Renewed se temb er a'z, i927;

This invention relatesto color light sigfroin caution to proceed; or viceversa, as is] nals for railway signaling purposes. frequently required the color screen would The need of visibility of a signal atflong gives .lnoinentary dangersignal when mm)- range, the necessity of a Widespread of ing front one eiitreineyposition to its other light and the advisahilityot keeping the extren'leposition Although'sueh falsernofis energy consninptionas loW as-possible, espenientarysignals are on the side of safety, in i cially where the energy isrderived from a that it is a dangeror red signal, .theconprin'iary battery, necessitates the, use. of an tinned recurrence otsuch false signalsyitis' ctlicient light projecting unit. .In the parbelieved, would nalre the engineer uncon ticnlar type of signal to which this invensciously@hesitate in. acting upon a danger 60 tion relates, a suitable reitlectoris employed signal Whenit first appears, which is of to make possible the utilization of as .much course a dangerous pract1ee,hecause-in some of the spherical candlepower aspracticable. instances such as approaching a crossover A reflector of this kind can not he used to and asi inilarintertering route, an immedibest advantage directly behinda lens of :1 ate application of the brakeshisj essential .65 particular'color for giving a certa in signal, Whena danger signal appears, Further; the tor'iit the lamp in such a reflectoris put out engineer;v especially it approaching a (la-11 so as not to give that particular signahthe geronspla ce, nayinake anemergencyapplilight from the sun or a locomotive headlight: cation 1 of the brakes unnecessarily, when i directed into the signal casing. niay be resucha nioinentary' dialse gdanger signal ;.is-l 0 fiected back and make it appear as though givein resultingin thelossottime and use the 'lighttherein were illuminated,thereby, less vear and tear on the 'railway equiplnent;. giving a false signal. ,Consequentlyifan ov-g With the ahove' and other considerations alele color screen should he used with a refl in inind, the principal object and purpose of flector, since it outside light is=thenrefleeted the present invention is toprovide means to, h hack, the proper signal indication Will 1; be. prevent the 1non'ientary flashing of a danger given, the color otthe light.reflected back or redfsignaltalselyin color light v signals heing' that corresponding totheposition of having inovable. color sereens operatedbyfa the color screen In a sense a movable color polarized; threeposition devicegand, another? an screen makes the reflector advantageous ohjeet of th'e'invention is to accomplish this 8 0 i rather than disadvantageous, in], that, it end Iby an arrangement of devices which would give. the proper signal due to light have established and recognizedrecords of: entering the signal bOX:IIIOlYlQlJhB Outside, performance,rather than by delicate .eoineven though the lamp filament is burned out. plicated and untried devices.

as In practice three indications are ordi- 0th r'ohjectsot the invention will appear; narily required, that is; danger caution-and as the descriptionprogresses, and Ithenovel proceed. In manyinstances the control for featnresfthereot iwill be pointed out in the' these indications obtained from a polar appended claims.

ized circuit and. relay, and thexcolor screen In describing the invention. in detail,

an is shifted by a polarized three positionrelay referencefwill he made to the accompanying i 45 tion when the relay is energized Ti- 1 1 p i d? n'ioveinent. In orderto have an arrange: (lraivingsgin WhlChE- y I inent tooperate'on the side ofsafety, it is Fig. l is avertical. longitudinal cross sec-' desirable to give a danger indication when tion taken [through the axis of a typicallight the .relay is deenergized "the caution indicav signal to which. the. invention may be appolarity and the. clear, indication tor the Fig. 2 isa diagrammatic pers iective viewf other polarity. In this arrangement the ot the .principal;bperating parts.of the dedanger signal screen will he loeatedfloevice-shown in Figql 'yand I tween the caution and proceed screens g an d Fig. a conventional diagrammatic v 50 \vhenthesignal indication is to hechanged illustrationiot theoperating devices ernhody we with a small aperture 3. A lens l'is positioned at one extreme end of the compartment, and a reflector 5 at the other extreme end of the compartment. A lamp 6 with a concentrated filament is located in the focus of the reflector 5, which reflects a large por tion of the spherical candle power therefrom so as to focus the light rays in the aperture in. the partition 3, from whence these rays are distributed on the lens, which further concentrates or converges them into the desired light beam. Adjacent the partition is a relatively light color screen orspectacle 7 comprising a sector having three color filters or glasses mounted therein to be alternately swung in front of the aperture. These glasses G, R and Y are preferably colored green, red and yellow respectively, thus placing the red in the middle of the sector 7. member 8, which in turn is pinned to a shaft 9 pivotally supported in socket or jewel bearings 10. The base member 8 is provided with shoulders 11 disposed on opposite sides of the shaft 9. Pivotally mounted on the shaft 9 are two'oppositely extending arms 12 normally resting on the shoulders 11 of the base, member 8, and having weights 13 integral therewith resting on stationary stops 14. It is obvious that when the shaft 9 is turned in one direction or the other, one of the weighted arms 12 will be raised from its stop 14, thus providing means for biasing the sector '7 to the middle position.

To the shaft 9 is also pinned a gear sector 15, meshing with a pinion 16 on the shaft 17 of a suitable polarized or three-position electro-inagnetic device. As shown, this threeposition electro-magnetic device is an alternating current relay P of the polyphase induction type having two field windings 1S and 19 and a shell-type rotor 20. Thedetail construction and operation of a relay of this type is well-known in the art, and for the purpose of obtaining a clear understanding of the present invention, it is, sufficient to note that torque is exerted on the rotor to turn it in one direction or theother depending upon the phase relationof the alternating currents in the two field windings; and thatthistorque ceases when current is cut off from one of these fieldwindings. Thus, by reversing the connections to one field winding, the rotor may be caused to rotate in either direction, and by breaking the electrical connection to this winding, the rotor is free to be moved by the weighted arms 12. For convenience, the position of the rotor and associated parts corresponding to the This sector '7 is riveted to a base deenergized condition of the relay, is termed the middle, intermediate or neutral position, and the positions of the rotor and associated parts corresponding too energization of the relay with different polarities, will be termed normal and reverse.

Pivotally connected to one corner of the base member 8 is a link 21 having its other end pivotally connected to an arm 22 extending from an insulating block 23 pivotally supported in socket, 01' jewel bearings 24-. On the block 23 are mounted two plates 25 each having parallel knife edges 25, the ends of the knife edges being provided with upstanding. lugs 2.5 A contact finger 26 is positioned to rest on said knife edges between the lugs of one of the plates 25, and is held yieldingly in this position by a compression coil spring 27,. which is held in place by a headed pin, passing through the finger and into the insu lating block 23. ()n the other end of the finger 26 is a pair ofcontact springs 28 riveted thereto to constitute a forked contact memberl Stationary adjustable contacts, shown ccinventionally as arrows, are disposed on opposite sides of the contact springs 28 so as to be engaged thereby when the spectacle 7 is in either of its extreme positions. The two contact springs 28 are spaced apart somewhat farther than ordi narily so as to engage their cooperating stationary contacts, when the block 23 is shifted to a small degreefrom its middle or neutral position shown in Fig. 2. In other words, the contacts of the finger 26 have what is known as a close adjustment. Another contact finger 29 of the usual form and similar in construction to, the one just described.

with springs .30, is secured to the block 23 on the other plate 25 and engages stationary contacts shown conventionally as arrows.

The circuit connections are established by both of these contact fingers 26 and 29 through a suitable flexible or pig-tail con motion 31 to the respective finger and thence through the contact springs 28 or 30'to the stationary contact engaged thereby. It is contemplated that the relay mechanism P, in addition to operating the color screen 7, will in practice also serve as a'track or line relay, and for this purpose any desired vnumberof other contact fingers, not shown,

will be carried by the block 23.

The operation of the light signal mechanisnijust described may be outlined briefly as follows. lVhen the relay P is energized with a polarity corresponding to clear or proceed traffic conditions, the rotor 20 drives the gear sector 15 in a clockwise direction, for example, rocking the color screen 7 to bring the green filter Gr opposite the opening3, so that the light rays emanating from the lamp 6 and projected from the signal will be colored green. .During this move ment the lefthan d weighted arm 12 is raised,

loo

lot

lac

and when the relay P is deenergi iied this Weighted arm returnsthe color screen 7,

gear sector 15, and rotor to the neutral" lamp r 6 when the signal -indicates clear or caution, and X which may be conveniently 70 r positionshown inFig. 2; hen the relay l? is energized-with.the oppositepolarity corresponding to cautionary traflie ()OIltll tions, the gear sector 1.5 is drivenin the op posits direction and rocks the colorscreen ,m, V I

t to br ng the yellow color lilter Y opposite the opetnng'S, givingayellow hean'iofllght.

lln this instance,thejright hund weighted arm 12 is raised, and when the relay Pis de energized, returns the partsl'o their neutral position. As the gear sector 15 and color screen 7 are shiftedi'the block 23' is rocked in a corresponding directionto close thenor-i I including a hack contact $6 of the slowrenull or reverse contactsj, 3

One arrangement of controlling circuits i enil'iodylng tlns'nivention and adaptetltobc used in connection with the particular type of signal shown in Figszl and 2, isillustratQ ed in a simplified and conventional manner- In Fig. 3. In th1s simplified c1rcuit dia-- gram, the relay P for operating the color screen 7 isshown conventionallyas comm-is in a local field windinglS and a track on line phase field winding 19. The local field \rii'lding 18 is permanently connected to a suitable source of alternating" current, sho vir as a transformer 82;vvhich is'of course con nected to a suitable transmission line or genmater: and the other field Winding" 19 is com'iected to the sarnesonrce' of 'ct'irr'e'nt through a suital'ilemeans for reversingfits connections. In Fig. 3fa siniple pole changing or reversing sivitch lgtl is shoivn ffor performing this function, and whilethis 'ivitch may be operated manually, in prac icetit; would ordinarily correspond to, contacts of a track or linerelay. or circuit" cont'r ),lling means associated with a signal"mechanism;

these var ous adaptations and" applications lieingr familiar to those skilledin the art) In accordan'e with thepresent'inventioin a suitable slow' releasinQrelay S'is assticitt' rd with the signal mechanism. This new releasing" relay 53 may he' o'ta ny suitf e coi' st uction, hut'in the application illustrated,

it shown conventionallyas a two-position tuoelcu'ient alternating-cur"cut relay of the induction type whichisniadeslow'relea g by, iiiroviding' a strong {local field acting in the \relduiownmanner to p'rodiice ai hrak+ my; o'l the rotor hvtheactionof eddy currents induced therein, as thereto]: is driven by thciu eipghted arms' hacltito its neutrahor dccnersrized position.

ahlesource of alternat ngcurrent; in this instance shown another transformer and the othertield Winding 36 of the sloiv releasing relay S is connected to thesalne This local .ficldsvind-jy ing; 34 is permanently connected to suitand correspondto' the finger 26 and itsas= SOCltItQCl stationarycontacts shown in Fig.2. The circuit for supplying current to the considered to be the normal lighting circuit, may be traced as -follo\vs:Starting, at one terminal 'Oii thesecondaryof transformer '35, wiresfii, '38 and lamp (3, wires 40 and L, through normal or reverse contacts of linger 29 of relay P, wires 42, 43, l4 and45, hack to other terminal of sa dsecondary. Tl'iereis an alternative or auxiliary circuit for supplying current to the lai'np' ti which includes a shunt. for the normalaud reverse contacts'ol the relay P this shunt is obviated, isas follows Assume the'parts andfcircnits" to be in the conditionjshown in r Fig.3, which corresponds tojthat exist/111g 901 when the'proceed or clear signal s to bQfCllS- played. \Vhen the sivitchll is shifted to the "dotted line position so a'sto reverse the I connections between the source 32 and the 'field winding 19 o'f the relay P, the rotor 20 isturned in the opposite direction, and commences the movement of the color screen 7 froniits existing'extreme" position to the other extreme position?[Aslthe rotor 20 commences itsfreturni movement-, contact bloclt lg is rocked,-'and somet-iinehefore the color screen Trenches itsmiddle or neutral posi tioin tlie finger 29 sepaifates from nor- I inal contact and: interrupts the imrmallight ing circuit', "so that 'asithe screen; passes through its middle position, thelalnpfi is extinguished, and the red indication is "not giivenf WVhen thea'elay P assumes ,its'full reverse position; the 'n'orn'lal lightingcircuit vfor the lamp '6 is againestablished at the re verse contact of thefingcir 29; In this uurv theliiinp ti extinguishedivhile the color 7 screen is passing throughits middle posi- "tion5 and consequently: although the red color filter R'passes' in front'ofi theopenin Brasit must necessarily do'in asignal mechanis'niofthisjtype,"the lamp isautoinatically entinguishedat the proper timetol avoid: the V projection of a beam of redLlight that would give an, objectionable*thoughn onientary falsestop'or langerindication. v Ks the signal"i'nechanisin is omnatedfrom the norm a]. or :proeee(lposition to the reverse or caution fposf iongythe energizing circuit for tlie slovv releasingrelay S "isinomentarily 13o interrupted at the contact finger 26, but on' account of the close adjustment of the contacts associated with this finger and the slow releasing properties of this relay, the back contact 46 of this relay is not closed during such a continuous change of the signal mechanism. The operation-tor a signal change from caution to clear is analogousto that described, and will be evident without detail explanation.

Next assume that the switch is shifted to the middle position, or the field winding 19 of the relay P is otherwise deenergized, this condition corresponding .toa stop or danger control. returned to its middle or neutral position by the weighted arm 12, which is raised at that time. During this movement of the signal mechanism, the normal lighting circuit for the lamp 6 is broken at the contact linger 529. Also, the energizing circuit for the slow releasing relay S is broken at the other con tact finger 2G; and after a shortinterval of time, the back contact iii of this slow releasiug. relay is closed to establish the auxiliary or alternative lighting circuit "for the lamp, thereby lighting the lamp to give the desired red or stop indication. The parts are preter ably selected and proportioned in practice so that the auxiliary lighting-circuit will be established as quickly after thesignal mechanism assumes ltsneutral or deenergized position, possible to attain, and also be sure with reasonable margins that this auxiliary circuit will not be closedas the signal mechanism changes continuously from one extreme condition to the other.

Fromthe foregoing it will be observed that there is provided by this invention a color light signal in which a movable color screen with the red filter in the middle is operated by a polarized orthree-position de vice, and in which the light is temporarily put out or cut off automaticallyas the color screen passes through its-imiddle position, so as to avoid flashing oi the red, while at the same time the light is permanently eflective to give the desired stop or danger indication when the color screencomes to rest in its middle position. It should be noted that the part and circuits constitut ing the inventionare organized to comply with the normally closed circuit principle, that is, failure on the side of safety. It the slow releasing relay S fails for any reason, the auxiliary lighting circuit is established,

assuring that a stop indicationwillbe given. In other words, the means utilized in this invention to prevent the objectionable flashing of the red, are such that any tailurewill not prevent the giving of the red indication when proper to do so. Failure of the back contact 46 of the slow releasing relay S, breakage of Wires, orother defects resulting in extinguishing the-lamp will of course re- The color screen 7 is now sult in the absence of any indication, but

the. engineer, having no signal to guide him,

will come to a stop or under control, in compliance with the usual rules.

lVhile the invention has been shown and described as embodying a signal mechanism of a particular type, and in connection with relays'operated by alternating current, it is evident that the same principles and functions may be employed in connection with other similar types of signals and with di rect current. Other modifications and adaptations of the specific embodiment of the in vention shown and described will beapparent to those skilled in the art, and I desire to have it understood that the particular parts and circuits herein disclosed are merely illustrative ot' the inventiomand do not exhaust the various embodin'ients ot the invention that may be made and used in a practical manner. 7

hat I claim is 1. In a light signal, an incandescent lamp and'on optical device for projecting light from saidlamp, a member comprising a plurality of color screens, means mounting said member for movement to an intermediate and two extreme positions to thereby interpose one of said screens in the path of the light, and means for extinguishing said lamp when said member is moved from one of its extreme positions to'the other.

2. In a light signal, a light source and an optical device for projecting light from said source, a member comprising a plurality of color screens, means mounting said member for movement to an intermediate and two extreme positions to thereby interpose one of said screens in the path of the light, said color screens allowing the emission of a light beam of different color for each of said positions, and means for extinguishing said light sourcewhen said member is moved continuously from one extreme position to the other and for illuminating said source when said member comes to rest in its intermediate position.

3. In alight signal, an incandescent lamp having an energizing circuit and an optical device for projecting light fronisaid lamp, a membercomprising a plurality or color screens, means mounting said member for movement to an intermediate and two extreme positions to thereby interpose one of said screens in the path of the light, said member being biased, to said intermediate position and said color screens allowing the emission of a light beam of different color tor each of said positions, circuit controlling means and means :tor'operating said circuit controlling means synchronously with the movement of said memberfor temporarily position, a three-position 'electro-magnetie device for moving said member and means for interrupting said energizing circuit for said lan'ip as said member moves through said intermediate position.

5. In a light signal, an incandescent lamp having a first lighting circuit and an optical device for projecting light from said lamp,

a second lighting circuit for the lamp, a.

, membercomprising a plurality of color screens, means mounting said member for movement to an intermediate and tWo extreme positions to thereby interpose one of said screens in the path of said light, means for interrupting said fixed lighting circuit when said member is in said intermediate position and independent means for closing said lighting circuit through the lamp'when said second member is at rest in said intermediate position. i

6. Ina light signal, an incandescent lamp and an optical device for projecting light from said lamp, a member comprising a. plurality of color screens, means mounting said member for movement to an intermediate and two extremepositions to thereby interpose one of said screens in the path ofthe light, an energizing circuit for said lamp, means for. interrupting said energizing cir cuit through said lamp when said member is in its intermediate position, and slow-acting means for closing another circuit through said lamp after said member remains at rest in its intermediate position for an interval of time.

7 In a light signal, an incandescent lamp and an optical device for projecting light from said lamp, a member comprising a plurality of color screens, means mounting-said member for movement to an intermediate and two extreme positions to thereby interpose one of said-screens in the path of the light, an energizing circuit for said lamp, a three-position electro-magnetic device for controlling the movement of said member to said positions, and slow-acting means controlled by said electro-magnetic device for controlling said energizing circuit for said lamp. r I v 8. In alight signal, an incandescent lamp and an optical device for projecting light from said lamp, a member comprising a plurality oi: color screens, means mountingsaid i member for movement to an intermediate and two extreme positions to-"thereby inteie v pose onef of said. screens in the path'of the light, an electro-re'sponsive device for-opsv crating, said l vmember "to said positions, a circuit jcontrolling's ineans operated by said, electro-i-esponsive device for closing an ener gizingcircuitthrough said laijnp only: when w j said member is in i said extreme positions, an auxiliary circuit for supplying energy to said lamp and means including a slow-acting device rendered ellective vvhen the electro-@ responsive device has assumed its intei' mediate position for establishing the auxiliary circuit after an interval ot delay. v

9. In a light signal, an incandescent lamp and an optical device tor-projecting light from said lamp, a member comprising a plurality oi colorscreens, means mounting said member 'for movement to an intermediate and two extreme positions to thereby interpQse one ot said screens in the path of the light, an electro-responsive device for'op erating'said member to said positions, a nor mally open energizing circuit including said lamp and slow-acting means-tor closing, said circuit, saidv slow-acting means being governed by said device and having its operation' initiated whenjsaid device operates said member to its intermediate position 10. In a light signal, an incandescentl'amp and an optical device for projecting light from said lamp, a member comprising a plurality of color screens, means mounting said member for movement to an intermediate and two extreme posit ons'to thereby inter pose one 01 said screens in the path of the light, a three-position electro-inagnetic de vice for operating said member, an energizing circuit for said lamp, means for closing said circuit only when, saiddevice moves said member to one or the other of its extrenie positions, a second energizing circuit forsaid lamp, :1. slow-acting relayhaving a back contact controlling said second energizing circuit, an energizingcircuit for said slovv=acting relay, and means for closing said last mentioned circuit only when said devicemov'esrsaid memberto one or theotlier of its extreme positions.

11. In a light signal, an incandescent lamp and an optical device for projecting light from said lamp, a member comprising aphirality of color screens, mea'ns mounting said member for movement to an intermediate and two extreme positions to thereby interpose one 01' said screens in the path of the light, sa dineiiil'ier being biased to said intermediate posit-ion, an yenergizing circuit for said lamp,- an alternating current relay for operating said member and for opening said energizing circuit when said member is n its llltBliDedlilbQ posit on, a sloW-releastie-energized respectively, assaid member ving alternating current relay energized and iso termediate position, and another energizing slow releasing relay having an energizing circuit for said lamp including a back concircuit including normal and reverse con- 10 tact of said slow-releasing relay. tacts of the first mentioned relay, and an 12. In a three-indication color light sigauxiliary circuit for said lamp including a 5 nal, the combination With a three-position back contact of theslow releasing relay.

relay governingthe indications of said sig- In testimony whereof I hereto afiix my nal, a light circuit for the-signal including signature;

normal and reverse contacts of said relay, :1 PAUL E. CARTER. 

